Exterior decks and similar outdoor wood platform structures are becoming ever more popular additions to houses. The value of such decking rests in enlargement of usable space for entertaining, etc., as well as enhancing the quality of outdoor activities such as cookouts or relaxation. Decking and its construction, like most residential construction, is subject to a multitude of variances in the nature of its size, placement, materials employed, etc. Also, the climate and temperatures to which the decking is exposed not only governs aspects of construction, due to expansion and contraction, but also of materials employed.
Referring to construction methods, currently the dominant method is commonly known as "stick built". This method entails a contractor going to the site, and constructing a deck the dimensions and configuration of which are unique to that site. Obviously, as a result, the majority of decks extant and currently under construction in the United States are non-uniform. Tolerances and crafting will differ from site-to-site as well as from worker-to-worker. Although certain construction standards exist, most notably those promulgated by BOCA, Building Official Code Administrators, it is difficult if not impossible to inspect each deck constructed to assure compliance with and adherence to those standards. Additionally, regional jurisdictions maintain specific requirements for outdoor decking. These requirements often vary due to the climate of the region. For example, regions subject to heavy snowfall often mandate stronger structures, i.e. 60 pounds per square foot (psf) rather than 40 psf. Therefore, the construction methods and materials employed should not only satisfy industry standards but also local regulations.
Moving to another factor concerning "stick built" construction methods, often many days if not weeks of labor are required to complete assembly of a deck. Conventionally, cement footers or supports are employed on which the remainder of the deck will be supported. They must first be made and then the deck itself is constructed on those footers. As previously indicated, the nature of the site as well as the character of the construction crew will be reflected in the finished structure. Hence, the "stick built" method defies simple elegant and uniform construction. Moreover, the structural integrity and strength of such decks are subject to wide variation.
At least one problem associated with "stick built" decks has been addressed by a development in the art field, uniformity. Kits of the "Egg Crate" type are now available which are predicated on the modular concept. These kits are available for professional installation as well as in the do-it-yourself market and can reduce costs. The kits contemplate assembly of substantially uniform, square wooden platforms which are dropped into a complementary frame structure constructed at the site. Conventional methods of frame and platform construction, although lending themselves to increased uniformity when employing the aforementioned kit concepts, often fail to provide decking structures meeting BOCA strength standards and even regional regulation.
One further consideration, critical in the final evaluation of decking, is aesthetics. It is not necessary to belabor this point. Suffice it to be stated that any decking must satisfy the tastes of its owner. If the structure is unsatisfactory as an architectural compliment to the attached edifice, the landscaping or the owner's tastes, the decking will detract from rather than enhance the enjoyment of the property.
Turning to one specific example of instructions for a kit deck, Better Homes and Gardens published a book entitled Deck and Patio Projects You Can Build in 1977. On pages 42-43, a modular terraced deck structure is described. This do-it-yourself project includes treating the lumber with preservative, preparing the site, forming a frame structure on the site where the frame includes ledgers adapted to have square plywood platforms seated thereon. This deck is fashioned to rest on the ground which constitutes the support for the frame. The frame, by disclosed construction, would fail to support a deck on footers or an elevated deck. This statement is supportable as the depicted frame structure, which is conventional, would be incapable of supporting required loads due to overstress. More particularly, the frame structure requires that each cross member be notched to permit interfitting, tight assembly. The primary strength source is provided by the three 2.times.10 boards being nailed together to form the border joists along two oppositely disposed edges which lie on the ground. If the platforms are assumed to be four foot square in an eight foot span, a forty pound live load will generate over 2500 psi. Given that the stress maximum for 2.times.10 lumber is 1750 psi, the overstress on the structure and corresponding bending would exceed 40%. Thus, it would be impossible to employ the structure with supporting posts or otherwise elevate the decking.